My invention relates to a device for making a perforation in film material, especially plastics film material, said device comprising a support for a plurality of perforating blades which is movable up and down.
In manufacturing products in plastics film material such as bags which are often produced in tube shaped film, with continuous manufacture in a production line having various operating stations, it is usual to make a perforation in the transverse direction which assures that the various unit lengths keep interconnected when passing along the line but are capable of being separated very easily when they are finished. When several layers of film lying upon each other are concerned, as is naturally the case when film tube is employed, this perforation is made in all layers. In similar cases it might be desirable, however, when one of the layers would be cut entirely, whilst the perforation, and thus the interconnection of the various units, exists only in one single layer. In this way tearing off the units would be easier because the force required for this purpose would reduced by half. This is of special importance when working up relatively thick film material, for example on the order of magnitude of 300 micron, which is used, for example, for heavy bags for industrial applications.